1. Field of the Invention
The present invention relates to a picture coding method and apparatus that code a moving picture by dividing each frame of the picture into parts and assigning the parts to different computing resources.
2. Description of the Related Art
With the increasing definition (resolution) of display apparatus in recent years has come the need to code high-definition moving pictures.
Moving picture coding has always been a computationally intensive task. The coding of moving pictures with the resolution of high-definition television (HDTV), for example, has required specialized hardware.
The performance of computing devices is also increasing, however, and this has led to proposed systems that code moving pictures in real time by assigning different parts of each frame to different computing resources. Japanese Patent Application Publication No. 9-294262, for example, describes a system that harnesses multiple hardware coders to operate concurrently on the separate parts. Japanese Patent No. 3621598 describes a similar multiprocessor system in which the multiple processors execute software to decode the different parts of each frame concurrently.
The coders in Japanese Patent Application Publication No. 9-294262 communicate with one another to transfer coding information so that in performing motion compensation, they can cross the boundaries between the different parts. The motion compensation areas of the different coders accordingly overlap. This overlapping scheme prevents the boundaries between different parts from becoming visible when the picture is decoded, but the disclosed scheme has the disadvantage of requiring a protocol analyzer and other tools to determine whether the coders are communicating correctly. Moreover, because of the special nature of the coding information being communicated, standard protocol analyzers or modified versions thereof cannot be used; it is necessary to develop a completely new protocol analyzer, which adds to the development cost and product cost of the coding apparatus.
A further problem is that the overlapping parts of each frame must be transmitted to both coders involved in the overlap, which uses up extra bandwidth on the data paths within the coding apparatus.